New discovery of Vintana tailbone provides insights into early mammalian evolution

Around 200 million years ago, Antarctica was connected to South America, Africa, India, and Australia in a supercontinent known as Gondwana. Within Gondwana, there existed a group of mammals called Gondwanatheria, which have intrigued paleontologists due to their limited fossil record. Shedding light on these enigmatic creatures, a team including Dr. Simone Hoffmann from the New York Institute of Technology and Dr. David Krause, Senior Curator at the Denver Museum of Nature and Science, has made significant discoveries. Their findings were published in the journal Cretaceous Research on May 15.

The study focuses on a gondwanatherian species named Vintana, which inhabited Madagascar approximately 66 million years ago, sharing the planet with dinosaurs. Vintana, meaning “lucky” in the Malagasy language, was initially known only from a fossilized skull described in a 2014 study conducted by Hoffmann, Krause, and colleagues. In 2020, the researchers unearthed a nearly complete skeleton of a gondwanatherian the size of a possum, nicknamed the “crazy beast” or Adalatherium. Prior to their latest study, Adalatherium’s skeleton was the sole postcranial remains found in the gondwanatherian fossil record.

The recent research by Hoffmann and Krause presents additional evidence of gondwanatherian postcranial remains and highlights a vertebral fossil that was identified as a tailbone from Vintana. Utilizing a micro-Computed Tomography (╬╝CT) scanner, the scientists analyzed the vertebra and compared its virtual surface files to the tail vertebrae of Adalatherium. They observed striking similarities, with the Vintana vertebra being 40 percent larger than its counterpart from Adalatherium. This size classifies it definitively as belonging to Vintana.

Although the discovery is limited to a single vertebra from Vintana’s larger skeleton, it offers crucial insights into the gondwanatherian lineage. Gondwanatherians possessed unusually short tail vertebrae, and the identification of the Vintana tailbone indicates that its tail was even wider and shorter than that of Adalatherium, which already had a stubby tail.

In summary, the research by Hoffmann and Krause expands our knowledge of gondwanatherians by providing additional postcranial evidence. The identification of a Vintana tailbone contributes to our understanding of these ancient mammals and their unique characteristics.

Source: New York Institute of Technology

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